<?php

namespace GetId3\Module\Audio;

use GetId3\Handler\BaseHandler;

/////////////////////////////////////////////////////////////////
/// GetId3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.mod.php                                        //
// module for analyzing MOD Audio files                        //
// dependencies: NONE                                          //
//                                                            ///
/////////////////////////////////////////////////////////////////

/**
 * module for analyzing MOD Audio files
 *
 * @author James Heinrich <info@getid3.org>
 *
 * @link http://getid3.sourceforge.net
 * @link http://www.getid3.org
 */
class Mod extends BaseHandler
{
    /**
     * @return bool
     */
    public function analyze()
    {
        $info = &$this->getid3->info;
        fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
        $fileheader = fread($this->getid3->fp, 1088);
        if (preg_match('#^IMPM#', $fileheader)) {
            return $this->getITheaderFilepointer();
        } elseif (preg_match('#^Extended Module#', $fileheader)) {
            return $this->getXMheaderFilepointer();
        } elseif (preg_match('#^.{44}SCRM#', $fileheader)) {
            return $this->getS3MheaderFilepointer();
        } elseif (preg_match('#^.{1080}(M\\.K\\.|M!K!|FLT4|FLT8|[5-9]CHN|[1-3][0-9]CH)#', $fileheader)) {
            return $this->getMODheaderFilepointer();
        }
        $info['error'][] = 'This is not a known type of MOD file';

        return false;
    }

    /**
     * @return bool
     */
    public function getMODheaderFilepointer()
    {
        $info = &$this->getid3->info;
        fseek($this->getid3->fp, $info['avdataoffset'] + 1080);
        $FormatID = fread($this->getid3->fp, 4);
        if (!preg_match('#^(M.K.|[5-9]CHN|[1-3][0-9]CH)$#', $FormatID)) {
            $info['error'][] = 'This is not a known type of MOD file';

            return false;
        }

        $info['fileformat'] = 'mod';

        $info['error'][] = 'MOD parsing not enabled in this version of GetId3Core() ['.$this->getid3->version().']';

        return false;
    }

    /**
     * @return bool
     */
    public function getXMheaderFilepointer()
    {
        $info = &$this->getid3->info;
        fseek($this->getid3->fp, $info['avdataoffset']);
        $FormatID = fread($this->getid3->fp, 15);
        if (!preg_match('#^Extended Module$#', $FormatID)) {
            $info['error'][] = 'This is not a known type of XM-MOD file';

            return false;
        }

        $info['fileformat'] = 'xm';

        $info['error'][] = 'XM-MOD parsing not enabled in this version of GetId3Core() ['.$this->getid3->version().']';

        return false;
    }

    /**
     * @return bool
     */
    public function getS3MheaderFilepointer()
    {
        $info = &$this->getid3->info;
        fseek($this->getid3->fp, $info['avdataoffset'] + 44);
        $FormatID = fread($this->getid3->fp, 4);
        if (!preg_match('#^SCRM$#', $FormatID)) {
            $info['error'][] = 'This is not a ScreamTracker MOD file';

            return false;
        }

        $info['fileformat'] = 's3m';

        $info['error'][] = 'ScreamTracker parsing not enabled in this version of GetId3Core() ['.$this->getid3->version().']';

        return false;
    }

    /**
     * @return bool
     */
    public function getITheaderFilepointer()
    {
        $info = &$this->getid3->info;
        fseek($this->getid3->fp, $info['avdataoffset']);
        $FormatID = fread($this->getid3->fp, 4);
        if (!preg_match('#^IMPM$#', $FormatID)) {
            $info['error'][] = 'This is not an ImpulseTracker MOD file';

            return false;
        }

        $info['fileformat'] = 'it';

        $info['error'][] = 'ImpulseTracker parsing not enabled in this version of GetId3Core() ['.$this->getid3->version().']';

        return false;
    }
}
